The present invention relates to a perpendicular recording magnetic head and a magnetic disk storage apparatus mounting the perpendicular recording magnetic head.
A magnetic disk storage apparatus comprises a magnetic recording medium and a magnetic head to read and write data on the magnetic recording medium with the magnetic head. To expand the recording capacity per unit area of the magnetic recording medium, the areal recording density must be increased. However, in the current longitudinal recording system, when the bit length to be recorded becomes small, the surface recording density cannot be increased due to thermal fluctuations in the magnetization of the medium. As a solution to this problem, there is a perpendicular recording system for recording a magnetization signal in a direction perpendicular to the medium.
The perpendicular recording system is divided into two types: one using a double-layer perpendicular medium comprising a soft under layer as a recording medium and the other using a single-layer perpendicular medium having no soft under layer. When the double-layer perpendicular medium is used as a recording medium, recording is carried out with a so-called “single pole head” having a main pole and an auxiliary pole. In this case, a large magnetic field can be applied to the medium. The shape of the air bearing surface of the main pole is desirably trapezoid with a narrow width on the leading side in consideration of a case where the head has a skew angle. FIG. 5 shows the structure of a magnetic head having a single pole head of the prior art. As shown in FIG. 5, the magnetic head of the prior art comprises a lower shield 8, read element 7, upper shield 9, auxiliary pole 3, thin film coils 2 and main pole 1 from the traveling direction (leading side) of the head in the mentioned order. The lower shield 8, read element 7 and upper shield 9 constitute a read head 24 and the auxiliary pole 3, thin film coils 2 and main pole 1 constitute a write head (single pole head) 25. The recording medium has a soft under layer 20 under a magnetic recording layer 19. JP-A No. 45008/2003 (Patent Document 1) discloses a single pole head having a stray-field shield recessed from the medium opposed surface on the main pole through a gap film.